Manufacture of esters



. products, free from halogen, may be con- Patented Aug. 4, 1931 UNITED. sT rEs PATENT OFFICE GERHARD STEIMMIG AND liEINRICH unmon, or LuDwIGsnArEN-oN-rnE-nnINE, GERMANY, AssIGNons I r0 I. c. ,rA nENINnUs'rru-E AKTIENGESELLSCHAFT, or FRANKFORT-ON-THE-MAIN, GERMANY, -A CORPORATION or GERMANY MANUFACTURE" or ESTERS No Drawing. Applicationtfiled February 3, 1927, Serial No. 165,751, and in Germany January 29, 1926.

It is known that alkylene oxids readily react with inorganic acids, to form unitary products, for example ethylene oxid furnishing ethylene-chlorhydrin with hydrochloric acid. On the other hand, in the case of or-. ganic acids, if any reaction occurs at all, it

only results in heterogeneous products, in

small yields.

W e have now found that aliphatic alkylene oxids, including their aliphatic substitution verted in a simple manner, into esters of glycol'or its homologues or derivatives with organic acids, if the alkyleneoxids, or their sub-.

.stitution products, be. treated with organic acids, or their anhydrides or substitution products all of which are equivalents for the purpose of the present invention, at an elevated temperature and in the presenceof cat alysts. The catalysts suitable for this reaction may be of most varied kinds. Especially such catalysts are suitable as are capable of p forming reactive complex compounds with the organic acid, which compounds are of stronger acidity than the free acid. As examples', thereof, acid salts of mineral acids,

salts of organic acids with. strong bases, and. the like may be mentioned. By the term elevated. temperature we wish' to. define :temperature'sbetween 55 and 170 C., the temperature of workin dependingto some degree on the acidity o the acids to bev esterfied and being usually somewhat above Depending on the catalyst employed and l the other conditions of working, such as the of glycols or mixtures of both. Even with a large excess of the or 'anic acid, mono-esters can be obtained aswi be more fully shownhereinafter in the examples. "Generally the tion may be carried out reaction proceeds in a practicallyquantitative manner.

The process accordin to the present inven-- f0! example by adding to an organic carboxylic .acid a small amount of a strong mineral acid e. sulfuric acid, or an acid reacting salt of sue an acid e, g. so-

trate how the said invention may be carried I into practical effect but the invention is not limited to these examples. The parts are by weight. Ewample 1 I Equimolecular uantities of acetic acid and ethylene oxid aredieated to a temperature of about 120 C. with the addition of 3 per cent of sodium acetate.

of the theoretical.

p l E example 2 v 4 To a boiling solution of l molecular pro: portions of glacial acetic acid and about 5 per cent of an alkali metal acetate there is added, under a reflux condenser, 1 molecular proportion'of an alkylene oxid. The monoacetic ester of the glycol corresponding to the alkylene oxid is obtained, in nearly quantitative 'yield.

" i I Example 3 264 arts of ethylene oxid areintroduccd into a oiling so ution-of 10 parts of concentrated sulfuridacid in ,360 parts of acetic anh dride under a reflux condenser.

yield of glycoldiacetate' is obtained.

Example I 167.5 parts of ethylene oxid are introduced -in a rapid stream while stirring actively into a mixture of 452 parts of glaclal'acetic acid.

Glycolmonoacetate is roduced, the yield being about 95 per cent 7 A good" and 8 parts of concentratedsulfuric acid boiling under a'reflux condenser. action proceeds rapidly and a good y1eld of glycol monoacetate is obtained, accompamed y small quantities oi diacetate and estersfififi The reof higher boiling point. Theoperation may also be conducted under pressure.

Emample' 5 122 kgs. of fused ,benzoic acid heated to 130, are mixed with 5 kgs. of sodium benzoate and the vapors of 25 kgs. of ethylene oxid passed in, while stirring, temperature being raised slowly to 170 C. In order 'to remove unchanged benzoic acid, the reaction mixture still warm is extracted with a dilute warm solution of sodium carbonate and after cooling and freezing the aqueous solution and: oily portions are filtered 01f. Glycoldibenzoate is left-on the filter and obtained in pure form (m. p. 73-7?) by crystallization from methanol.

We claim:

1. The process of producing esters of glycols with organic acids which comprises acting on an organic acid with an aliphatic alkylene oxid at an elevated temperature and in the presence of a catalyst selected from the class consisting of acid salts of mineral acids and salts of organic acids with strong bases, which, under the conditions of working, form a reactive complex compound with said first named organicacid which is of a stronger acidity than said organicacid.

2. The process of producing esters of ethylene glycol with organic acids which comprises acting on an organic acid with ethylene oxid at an elevated temperature and in the presence of a catalyst selected from the class consisting of acid salts of mineral acids and salts of organic acids with strong bases, which, under the conditions of work ing, form a reactive complex compound with said first named organic acid which is of a stronger acidity than said organic acid.

The process of producing mono esters of glycols with organic acids which cornprises acting on an organic acid, with an alset our hands:

ature of about 120 C. in the presence of sodium acetate.

6. The process of producing 'mono esters of glycols with organic acids which comprises acting onan organic acid with an alkylene oxide atan elevated temperature and in the presence of sodium bisulfate.

7. The process of producing propylene glycol diacetate which comprises acting on acetic acid with propylene oxide at a temperature of about 120 C. in the presence of sodium bisulfate.

8. The process of producing glycol benzoate which comprises treating fused benzoic acid with ethylene oxide at a temperature of about 170 C. in the presence of sodium benzoate. i

In testimony whereof we have hereunto .GERHARD STEIMMIG. HEINRICH ULRICH.

kylene oxid at an elevated temperature and r I in the presence of alkali metal acetate.

' 4. The process of producing ethylene glycol mono-acetate which comprises acting on' acetic acid with ethylene oxid at an elevated temperature in the presence of, alkali-metal acetate.

5. Theprocess of producing ethylene gl ycol mono-acetate which comprises acting on acetic acid with ethylene oxide at a temper- 

